Measurement device and measurement method, exposure apparatus and exposure method, and device manufacturing method

ABSTRACT

An alignment system is equipped with: an alignment system having an objective optical system, an irradiation system and a beam receiving system; and a calculation system, the objective optical system including an objective transparent plate that faces a wafer movable in a Y-axis direction, the irradiation system irradiating a grating mark provided at the wafer with measurement beams via the objective transparent plate while scanning the measurement beams in the Y-axis direction, the beam receiving system receiving diffraction beams from the grating mark of the measurement beams via the objective optical system, and the calculation system obtaining positional information of the grating mark on the basis of the output of the beam receiving system, wherein the objective transparent plate deflects or diffracts the diffraction beams diffracted at the grating mark toward the beam receiving system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/627,707 filed on Jun. 20, 2017, which is a continuation ofInternational Patent Application No. PCT/JP2015/085848, with aninternational filing date of Dec. 22, 2015, claiming priority fromJapanese Patent Application No. 2014-259759 filed Dec. 24, 2014, thedisclosures of the above applications being incorporated herein byreference in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to measurement devices and measurementmethods, exposure apparatuses and exposure methods, and devicemanufacturing methods, and more particularly to a measurement device anda measurement method to obtain positional information of grating marksprovided at an object, an exposure apparatus equipped with themeasurement device and an exposure method using the measurement method,and a device manufacturing method using the exposure apparatus or theexposure method.

Description of the Background Art

Conventionally, in a lithography process for manufacturing electronicdevices (micro devices) such as semiconductor devices (integratedcircuits and the like), and liquid crystal display devices, a projectionexposure apparatus of a step-and-scan method (a so-called scanningstepper (which is also called a scanner)) and the like are used.

In this type of exposure apparatuses, for example, since plural layersof patterns are formed and overlaid on a wafer or a glass plate(hereinafter, generically referred to as a “wafer”), an operation (aso-called alignment) for optimizing a relative positional relationshipbetween a pattern already formed on the wafer and a pattern that a maskor a reticle (hereinafter, generically referred to as a “reticle”) hasis performed. Further, as an alignment system (sensor) used in this typeof alignment, the one that performs detection of a grating mark providedon the wafer by scanning a measurement beam with respect to the gratingmark (causing the measurement beam to follow the grating mark) is known(e.g., refer to U.S. Pat. No. 8,593,646).

In this type of alignment systems, however, since the measurement beamis scanned, an objective optical system including an objective lens isrequired to have a wide field of view. However, in the case of simplywidening the field of view of the objective lens, the objective opticalsystem including the objective lens increases in size.

SUMMARY OF THE INVENTION

According to a first aspect, there is provided a measurement device,comprising: a mark detection system that has an irradiation system, anobjective optical system and a beam receiving system, the irradiationsystem irradiating a grating mark provided at an object that is moved ina first direction, with a measurement beam, while scanning themeasurement beam in the first direction with respect to the gratingmark, the objective optical system including an objective opticalelement capable of facing the object that is moved in the firstdirection, and the beam receiving system receiving a diffraction beamfrom the grating mark of the measurement beam via the objective opticalsystem; and a calculation system that obtains positional information ofthe grating mark on the basis of a detection result of the markdetection system, wherein the objective optical element deflects ordiffracts the diffraction beam generated at the grating mark toward thebeam receiving system.

According to a second aspect, there is provided an exposure apparatus,comprising: the measurement device related to the first aspect; aposition control device that controls a position of the object on thebasis of an output of the measurement device; and a pattern formationdevice that forms a predetermined pattern on the object by irradiatingthe object with an energy beam.

According to a third aspect, there is provided an exposure apparatus,comprising: the measurement device related to the first aspect, whereina predetermined pattern is formed on the object by irradiating theobject with an energy beam, while controlling a position of the objecton the basis of an output of the measurement device.

According to a fourth aspect, there is provided an exposure apparatusthat forms a predetermined pattern on an object by irradiating theobject with an energy beam, the apparatus comprising: a mark detectionsystem that has an irradiation system, an objective optical system and abeam receiving system, the irradiation system irradiating a grating markprovided at the object that is moved in a first direction, with ameasurement beam, while scanning the measurement beam in the firstdirection with respect to the grating mark, the objective optical systemincluding an objective optical element capable of facing the object thatis moved in the first direction, and the beam receiving system receivinga diffraction beam from the grating mark of the measurement beam via theobjective optical system, wherein the diffraction beam generated at thegrating mark is deflected or diffracted, by the objective opticalsystem, toward the beam receiving system, and a position of the objectis controlled on the basis of a detection result of the mark detectionsystem.

According to a fifth aspect, there is provided a device manufacturingmethod, comprising: exposing a substrate using the exposure apparatusrelated to anyone of the second aspect to the fourth aspect; anddeveloping the substrate that has been exposed.

According to a sixth aspect, there is provided a measurement method ofmeasuring positional information of a grating mark provided at anobject, the method comprising: moving the object in a first direction,below an objective optical system including an objective optical elementcapable of facing the object; irradiating the grating mark of the objectthat is moved, with a measurement beam, while scanning the measurementbeam in the first direction with respect to the grating mark; receivinga diffraction beam from the grating mark of the measurement beam with abeam receiving system via the objective optical system; and obtainingpositional information of the grating mark on the basis of an output ofthe beam receiving system, wherein the objective optical system deflectsor diffracts the diffraction beam generated at the grating mark, towardthe beam receiving system.

According to a seventh aspect, there is provided an exposure method,comprising: measuring positional information of a grating mark providedat an object using the measurement method related to the sixth aspect;and exposing the object with an energy beam, while controlling aposition of the object on the basis of the positional information of thegrating mark that has been measured.

According to an eighth aspect, there is provided a device manufacturingmethod, comprising: exposing a substrate using the exposure methodrelated to the seventh aspect; and developing the substrate that hasbeen exposed.

BRIEF DESCRIPTION OF DRAWINGS

In the accompanying drawings;

FIG. 1 is a view schematically showing a configuration of an exposureapparatus related a first embodiment;

FIG. 2a to FIG. 2c are views showing examples (No. 1 to No. 3) ofgrating marks formed on a wafer;

FIG. 3 is a view showing a configuration of an alignment system that theexposure apparatus in FIG. 1 has;

FIG. 4a is a plan view of an objective transparent plate that thealignment system in FIG. 3 has, and FIG. 4b is a view showingdiffraction beams incident on the objective transparent plate;

FIG. 5a is a plan view of a grating plate for detection that thealignment system in FIG. 3 has, and FIG. 5b is a view showing an exampleof a signal obtained from a beam receiving system that the alignmentsystem in FIG. 3 has;

FIG. 6 is a block diagram showing a control system of the exposureapparatus;

FIG. 7a is a plan view of an objective transparent plate that analignment system related to a second embodiment has, and FIG. 7b is aview showing diffraction beams incident on the objective transparentplate in FIG. 7 a;

FIG. 8a is a view showing a modified example of a grating mark, and FIG.8b is a plan view of an objective transparent plate used to detect thegrating mark in FIG. 8 a;

FIG. 9 is a view showing a modified example of a beam receiving systemof an alignment system; and

FIG. 10 is a plan view of an objective transparent plate related to amodified example.

DESCRIPTION OF EMBODIMENTS First Embodiment

A first embodiment will be discussed below, on the basis of FIGS. 1 to6.

FIG. 1 schematically shows a configuration of an exposure apparatus 10related to the first embodiment. Exposure apparatus 10 is a projectionexposure apparatus of a step-and-scan method, which is a so-calledscanner. As will be described later, in the present embodiment, aprojection optical system 16 b is provided, and in the descriptionbelow, the explanation is given assuming that a direction parallel to anoptical axis AX of projection optical system 16 b is a Z-axis direction,a direction in which a reticle R and a wafer W are relatively scannedwithin a plane orthogonal to the Z-axis direction is a Y-axis direction,a direction orthogonal to the Z-axis and the Y-axis is an X-axisdirection, and rotation (tilt) directions around the X-axis, the Y-axisand the Z-axis are θx, θy and θz directions, respectively.

Exposure apparatus 10 is equipped with: an illumination system 12; areticle stage 14; a projection unit 16; a wafer stage device 20including a wafer stage 22; a multipoint focal position measurementsystem 40; an alignment system 50; a control system thereof; and thelike. In FIG. 1, wafer W is placed on wafer stage 22.

As is disclosed in, for example, U.S. Patent Application Publication No.2003/0025890 and the like, illumination system 12 includes: a lightsource; and an illumination optical system that has an illuminanceuniformizing optical system having an optical integrator, and a reticleblind (none of which is illustrated). Illumination system 12 illuminatesan illumination area IAR having a slit-like shape elongated in theX-axis direction on reticle R set (restricted) by the reticle blind (amasking system) with illumination light (exposure light) IL with almostuniform illuminance. As illumination light IL, for example, an ArFexcimer laser beam (with a wavelength of 193 nm) is used.

On reticle stage 14, reticle R having a pattern surface (a lower surfacein FIG. 1) on which a circuit pattern and the like are formed is fixedby, for example, vacuum adsorption. Reticle stage 14 is finely drivablewithin an XY plane and also drivable at a predetermined scanningvelocity in a scanning direction (the Y-axis direction that is a lateraldirection on the page surface of FIG. 1), with a reticle stage drivesystem 32 (not illustrated in FIG. 1, see FIG. 6) including, forexample, a linear motor and the like. Positional information within theXY plane (including rotation information in the θz direction) of reticlestage 14 is constantly measured at a resolution of, for example, around0.5 to 1 nm with a reticle stage position measurement system 34including, for example, an interferometer system (or an encoder system).The measurement values of reticle stage position measurement system 34are sent to a main controller 30 (not illustrated in FIG. 1, see FIG.6). Main controller 30 controls the position (and the velocity) ofreticle stage 14 by calculating the position of reticle stage 14 in theX-axis direction, the Y-axis direction and the θz direction on the basisof the measurement values of reticle stage position measurement system34 and controlling reticle stage drive system 32 on the basis of thiscalculation result. Further, exposure apparatus 10 is equipped with areticle alignment system 18 (see FIG. 6) for performing positiondetection of reticle alignment marks formed on reticle R, though thereticle alignment system is not illustrated in FIG. 1. As reticlealignment system 18, an alignment system having a configuration asdisclosed in, for example, U.S. Pat. No. 5,646,413, U.S. PatentApplication Publication No. 2002/0041377 and the like can be used.

Projection unit 16 is disposed below reticle stage 14 in FIG. 1.Projection unit 16 includes a lens barrel 16 a and projection opticalsystem 16 b stored within lens barrel 16 a. As projection optical system16 b, for example, a dioptric system composed of a plurality of opticalelements (lens elements) arrayed along optical axis AX parallel to theZ-axis direction is used. Projection optical system 16 b is, forexample, both-side telecentric, and has a predetermined projectionmagnification (such as ¼ times, ⅕ times or ⅛ times). Therefore, whenillumination area IAR on reticle R is illuminated with illuminationsystem 12, by illumination light IL, which has passed through reticle Rwhose pattern surface is disposed almost coincident with a first plane(an object plane) of projection optical system 16 b, a reduced image ofa circuit pattern (a reduced image of a part of the circuit pattern) ofreticle R within illumination area IAR is formed via projection opticalsystem 16 b (projection unit 16) onto an area (hereinafter, alsoreferred to as an exposure area) IA, conjugate with illumination areaIAR described above, on wafer W whose surface is coated with resist(sensitive agent) and which is disposed on a second plane (an imageplane) side of projection optical system 16 b. Then, by synchronousdriving of reticle stage 14 and wafer stage 22, reticle R is moved inthe scanning direction (the Y-axis direction) relative to illuminationarea IAR (illumination light IL) and also wafer W is moved in thescanning direction (the Y-axis direction) relative to exposure area IA(illumination light IL), and thereby the scanning exposure of one shotarea (a divided area) on wafer W is performed and the pattern of reticleR is transferred onto the shot area. That is, in the present embodiment,a pattern is generated on wafer W by illumination system 12, reticle Rand projection optical system 16 b, and the pattern is formed on wafer Wby exposure of a sensitive layer (a resist layer) on wafer W withillumination light IL.

Wafer stage device 20 is equipped with wafer stage 22 disposed above abase board 28. Wafer stage 22 includes a stage main body 24, and a wafertable 26 mounted on stage main body 24. Stage main body 24 is supportedon base board 28, via a clearance (an interspace, or a gap) of aroundseveral μm, by noncontact bearings (not illustrated), e.g., airbearings, fixed to the bottom surface of stage main body 24. Stage mainbody 24 is configured drivable relative to base board 28 in directionsof three degrees of freedom (X, Y, θz) within a horizontal plane, by awafer stage drive system 36 (not illustrated in FIG. 1, see FIG. 6)including, for example, a linear motor (or a planar motor). Wafer stagedrive system 36 includes a fine drive system that finely drives wafertable 26 relative to stage main body 24 in directions of six degrees offreedom (X, Y, Z, θx, θy and θz). Positional information of wafer table26 in the directions of six degrees of freedom is constantly measured ata resolution of, for example, around 0.5 to 1 nm with a wafer stageposition measurement system 38 including, for example, an interferometersystem (or an encoder system). The measurement values of wafer stageposition measurement system 38 are sent to main controller 30 (notillustrated in FIG. 1, see FIG. 6). Main controller 30 controls theposition (and the velocity) of wafer table 26 by calculating theposition of wafer table 26 in the directions of six degrees of freedomon the basis of the measurement values of wafer stage positionmeasurement system 38 and controlling wafer stage drive system 36 on thebasis of this calculation result. Main controller 30 also controls theposition of stage main body 24 within the XY plane on the basis of themeasurement values of wafer stage position measurement system 38.

Multipoint focal position measurement system 40 is a positionmeasurement device of an oblique incidence method that measurespositional information of wafer W in the Z-axis direction, which has aconfiguration similar to the one disclosed in, for example, U.S. Pat.No. 5,448,332 and the like. As illustrated in FIG. 1, multipoint focalposition measurement system 40 is disposed on the further −Y side ofalignment system 50 disposed on the −Y side of projection unit 16. Sincethe output of multipoint focal position measurement system 40 is usedfor autofocus control that will be described later, multipoint focalposition measurement system 40 is referred to as an AF system 40hereinafter.

AF system 40 is equipped with: an irradiation system that irradiates thewafer W surface with a plurality of detection beams; and a beamreceiving system that receives reflection beams, from the wafer Wsurface, of the plurality of detection beams (none of these systems isillustrated). A plurality of detection points of AF system 40(irradiation points of the detection beams) are disposed at apredetermined interval along the X-axis direction on a surface to bedetected, though the illustration of the detection points is omitted. Inthe present embodiment, for example, the detection points are disposedin a matrix shape having one row and M columns (M is a total number ofthe detection points) or 2 rows and N columns (N is a half of the totalnumber of the detection points). The output of the beam receiving systemis supplied to main controller 30 (see FIG. 6). Main controller 30obtains positional information in the Z-axis direction of the wafer Wsurface (surface position information) at the plurality of detectionpoints on the basis of the output of the beam receiving system. In thepresent embodiment, the length in the X-axis direction of a detectionarea of the surface position information by AF system 40 (a disposedarea of the plurality of detection points) is set equal to at least thelength in the X-axis direction of one shot area set on wafer W.

Prior to an exposure operation, main controller 30 moves wafer Wrelative to the detection area of AF system 40 in the Y-axis directionand/or the X-axis direction as needed, and acquires the surface positioninformation of wafer W on the basis of the output of AF system 40 atthat time. Main controller 30 performs the acquisition of the surfaceposition information as described above for all the shot areas set onwafer W, and associates the results of the acquisition with thepositional information of wafer table 26 to store them as focus mappinginformation.

Next, alignment marks formed on wafer W and alignment system 50 of anoff-axis type used in detection of the alignment marks will bedescribed.

As a detection subject by alignment system 50, at least one grating markGM as illustrated in FIG. 2a is formed in each shot area on wafer W.Note that actually grating mark GM is formed in a scribe line of eachshot area.

Grating mark GM includes a first grating mark GMa and a second gratingmark GMb. The first grating mark GMa is made up of a reflection-typediffraction grating in which grating lines extending in a direction(hereinafter, referred to as an α direction for the sake of convenience)that is at a 45 degree angle with respect to the X-axis within the XYplane are formed at a predetermined interval (e.g., a pitch P1 (P1 is anarbitrary numerical value)) in a direction (hereinafter, referred to asa β direction for the sake of convenience) orthogonal to the α directionwithin the XY plane, and which has a period direction in the βdirection. The second grating mark GMb is made up of a reflection-typediffraction grating in which grating lines extending in the β directionare formed at a predetermined interval (e.g., a pitch P2 (P2 is anarbitrary numerical value)) in the α direction, and which has a perioddirection in the α direction. The first grating mark GMa and the secondgrating mark GMb are disposed consecutively (adjacently) in the X-axisdirection so that the positions of the first grating mark GMa and thesecond grating mark GMb in the Y-axis direction are the same. Note that,in FIG. 2a , the pitch of the grating is illustrated considerably widerthan the actual pitch for the sake of convenience for illustration. Thesame is true for diffraction gratings as illustrated in the otherdrawings. Incidentally, pitch P1 and pitch P2 may be the same numericalvalue or may be the numerical values different from each other. Further,although the first grating mark GMa and the second grating mark GMb arein contact with each other in FIG. 2, they need not be in contact witheach other.

As illustrated in FIG. 3, alignment system 50 is equipped with: a lightsource 72 that emits a plurality of measurement beams L1 and L2; anobjective optical system 60 that includes an objective transparent plate(which is also referred to as an objective optical element) 62 disposedfacing wafer W; an irradiation system 70 that irradiates grating mark GMon wafer W with measurement beams L1 and L2 via objective transparentplate 62 while scanning the measurement beams L1 and L2 in the scanningdirection (which is the Y-axis direction in the present embodiment andis also referred to as “a first direction” as needed); and a beamreceiving system 80 that receives, via objective optical system 60,diffraction beams ±L3 and ±L4 from grating mark GM based measurementbeams L1 and L2.

Irradiation system 70 is equipped with: light source 72 described above;a movable mirror 74 disposed on optical paths of measurement beams L1and L2; a half mirror (a beam splitter) 76 that reflects parts ofmeasurement beams L1 and L2 reflected by movable mirror 74 toward waferW and transmits the rest of the measurement beams; a beam positiondetection sensor 78 disposed on optical paths of measurement beams L1and L2 transmitted (having passed) through half mirror 76; and the like.

Light source 72 emits two measurement beams L1 and L2 having a broadbandwavelength, to which the resist coated on wafer W (see FIG. 1) isinsensitive, in the −Z direction. Note that, in FIG. 3, the optical pathof measurement beam L2 overlaps with the optical path of measurementbeam L1, on the depth side of the paper surface. In the present firstembodiment, as measurement beams L1 and L2, for example, white light isused.

As movable mirror 74, for example, the well-known galvano mirror is usedin the present embodiment. Movable mirror 74 has a reflection surfacefor reflecting measurement beams L1 and L2 that is configured capable ofmoving rotationally (rotating) around an axis line parallel to theX-axis. The angle of rotational movement of movable mirror 74 iscontrolled by main controller 30 (not illustrated in FIG. 3, see FIG.6). The angle control of movable mirror 74 will be further describedlater. Incidentally, an optical member (e.g., a prism or the like) otherthan the galvano mirror may be used, as far as such an optical membercan control the reflection angle of measurement beams L1 and L2.

The position (the angle of a reflection surface) of half mirror 76 isfixed, which is different from movable mirror 74. The optical paths ofthe parts of measurements beams L1 and L2 reflected off the reflectionsurface of movable mirror 74 are bent to the −Z direction by half mirror76, and then the parts of measurements beams L1 and L2 are incidentalmost perpendicularly on grating mark GM formed on wafer W, viaobjective transparent plate 62. Note that, in FIG. 3, movable mirror 74is inclined at a 45 degree angle with respect to the Z-axis, and theparts of measurement beams L1 and L2 from movable mirror 74 arereflected off half mirror 76 in a direction parallel to the Z-axis.Further, although only movable mirror 74 and half mirror 76 are disposedon the optical paths of measurement beams L1 and L2 between light source72 and objective transparent plate 62 in FIG. 3, irradiation system 70is configured so that measurement beams L1 and L2 emitted from objectivetransparent plate 62 are almost perpendicularly incident on grating markGM formed on wafer W even in the case where movable mirror 74 isinclined at an angle other than a 45 degree angle with respect to theZ-axis. In this case, on the optical paths of measurement beams L1 andL2 between light source 72 and objective transparent plate 62, at leastone optical member that is different from movable mirror 74 and halfmirror 76 may be disposed. Measurement beams L1 and L2 having passed(transmitted) through half mirror 76 are incident on beam positiondetection sensor 78 via a lens 77. Beam position detection sensor 78 hasa photoelectric conversion element such as a PD (Photo Detector) arrayor a CCD (Charge Coupled Device), and its imaging plane is disposed on aplane conjugate with the wafer W surface.

Here, as illustrated in FIG. 2a , the distance between measurement beamsL1 and L2 is set so that, of measurement beams L1 and L2 emitted fromlight source 72, measurement beam L1 is irradiated on the first gratingmark GMa and measurement beam L2 is irradiated on the second gratingmark GMb. In alignment system 50, when the angle of the reflectionsurface of movable mirror 74 is changed, the respective incidence(irradiation) positions of measurement beams L1 and L2 on grating marksGMa and GMb (wafer W) are changed in the scanning direction (the Y-axisdirection, the first direction) in accordance with the angle of thereflection surface of movable mirror 74 (see outlined arrows in FIG. 2).Further, in conjunction with the positional change on grating mark GM ofmeasurement beams L1 and L2, the incidence positions of measurementbeams L1 and L2 on beam position detection sensor 78 (see FIG. 3) arealso changed. The output of beam position detection sensor 78 issupplied to main controller 30 (not illustrated in FIG. 2, see FIG. 6).Main controller 30 can obtain irradiation position information ofmeasurement beams L1 and L2 on wafer W on the basis of the output ofbeam position detection sensor 78.

Objective optical system 60 is equipped with objective transparent plate62, a detector-side transparent plate 64 and a grating plate 66.Objective transparent plate 62 is formed, into roughly a square shape ina planar view, of a transparent (light-transmissible) material, e.g., aquartz glass or the like, and objective transparent plate 62 includes amain section 62 a disposed almost parallel to a horizontal plane and aplurality of transmission type diffraction gratings (hereinafter, simplyreferred to as “diffraction gratings”) formed on the lower surface ofthe main section 62 a. FIG. 4a shows a plan view of objectivetransparent plate 62 when viewed from the lower surface side (the −Zside).

On the lower surface of main section 62 a, diffraction gratings(diffraction gratings Ga₁ and Ga₂) with a period direction in the βdirection and diffraction gratings (diffraction gratings Gb₁ and Gb₂)with a period direction in the α direction are formed. A grating pitchof each of diffraction gratings Ga₁, Ga₂, Gb₁ and Gb₂ is set to the samevalue in design as the grating pitches (P1 and P2 described above) ofgrating mark GMa and GMb (see FIG. 2a for each of them). Diffractiongratings Ga₁ and Ga₂ are disposed apart from each other in the βdirection and diffraction gratings Gb₁ and Gb₂ are disposed apart fromeach other in the α direction. Further, diffraction gratings Ga₁ to Gb₂are each formed so as to avoid the center portion of main section 62 a.As illustrated in FIG. 3, measurement beams L1 and L2 whose opticalpaths are bent to the −Z direction by half mirror 76 pass (aretransmitted) through the center portion of main section 62 a and areirradiated on grating mark GM. Of main section 62 a of objectivetransparent plate 62, an area including the center portion describedabove (an area where diffraction gratings Ga₁, Ga₂, Gb₁ and Gb₂ are notformed) is referred to as a “transmissive area” or a “first area”.Further, diffraction grating Ga₁ and/or diffraction grating Gb₁ are/isalso referred to as (a) first optical component(S), and diffractiongrating Ga₂ and/or diffraction grating Gb₂ are/is also referred to as(a) second optical component(s).

In alignment system 50, as illustrated in FIG. 4b , in a state wheregrating mark GM (GMa and GMb) is located directly under the transmissivearea in main section 62 a, measurement beam L1 is irradiated on thefirst grating mark GMa via the transmissive area. Then, a plurality of+first-order diffraction beams (+L3), based on measurement beam L1,generated from the first grating mark GMa are incident on diffractiongrating Ga₁, and a plurality of −first-order diffraction beams (−L3),based on measurement beam L1, generated from the first grating mark GMaare incident on diffraction grating Ga₂. Similarly, when measurementbeam L2 is irradiated on the second grating mark GMb via thetransmissive area, a plurality of +first-order diffraction beams (+L4),based on measurement beam L2, generated from the second grating mark GMbare incident on diffraction grating Gb₁, and a plurality of −first-orderdiffraction beams (−L4), based on measurement beam L2, generated fromthe second grating mark GMb are incident on diffraction grating Gb₂.Note that in the case where white light is used as measurement beams L1and L2 as in the present embodiment, a plurality of −first-orderdiffraction beams and a plurality of +first-order diffraction beams,according to beams with a plurality of wavelengths included in the whitelight, are to be generated.

The +first-order diffraction beams (+L3 and +L4) are diffracted bydiffraction gratings Ga₁ and Gb₁, respectively, and the −first-orderdiffraction beams (−L3 and −L4) are diffracted by diffraction gratingsGa₂ and Gb₂, respectively. At this time, a predetermined-orderdiffraction beams, of measurement beams L1 and L2, generated by thesetting of the grating pitch of each of grating marks GMa and GMb anddiffraction gratings Ga₁, Ga₂, Gb₁ and Gb₂ corresponding to thesegrating marks, which are the respective −first-order diffraction beamsof the +first-order diffraction beams (+L3 and +L4) and the respective+first-order diffraction beams of the −first-order diffraction beams(−L3 and −L4), travel parallel to an optical axis of objective opticalsystem 60 (see FIG. 3) (parallel to the Z-axis direction) toward beamreceiving system 80 (see FIG. 3). Further, the respective zero-orderdiffraction beams from grating marks GMa and GMb of measurement beams L1and L2 are to be attenuated because any diffraction gratings are notformed in the center portion of objective transparent plate 62 (i.e.,the surface state of the transmissive area and the surface state of anarea where diffraction gratings Ga₁ to Gb₂ are formed are opticallydifferent). Although it is preferable in this case that the respectivezero-order diffraction beams from grating marks GMa and GMb ofmeasurement beams L1 and L2 are intercept (impeded) from travelling tobeam receiving system 80 (see FIG. 3), these zero-order diffractionbeams maybe attenuated at least in a range to prevent them from becomingmeasurement noise in beam receiving system 80.

The respective predetermined-order diffraction beams describedpreviously of the ±first-order diffraction beams (±L3 and ±L4) emittedfrom objective transparent plate 62 (hereinafter, also referred to,collectively, as the diffraction beams from objective transparent plate62) are incident on detector-side transparent plate 64 disposed aboveobjective transparent plate 62, as illustrated in FIG. 3.

Since the configuration and the functions of detector-side transparentplate 64 are substantially the same as those of objective transparentplate 62, the description thereof will be omitted. That is, thediffraction beams from objective transparent plate 62 that are incidenton detector-side transparent plate 64 are incident on transmission typediffraction gratings formed on the lower surface of a main section 64 aof detector-side transparent plate 64, and thereby diffracted (theiroptical paths are bent), and are incident on grating plate 66 disposedabove detector-side transparent plate 64.

Grating plate 66 is made up of a plate-shaped member extending parallelto the Y-axis direction that is disposed parallel to detector-sidetransparent plate 64. As illustrated in FIG. 5a , readout diffractiongratings Ga and Gb are formed on grating plate 66. Readout diffractiongrating Ga is a transmission type diffraction grating with a perioddirection in the β direction that corresponds to grating mark GMa (seeFIG. 2a ). Readout diffraction grating Gb is a transmission typediffraction grating with a period direction in the α direction thatcorresponds to grating mark GMb (see FIG. 2a ).

When performing position measurement of grating mark GM using alignmentsystem 50, main controller 30 (see FIG. 6) controls movable mirror 74 ofalignment system 50 while driving grating mark GM (i.e., wafer W) in theY-axis direction (the first direction) relative to objective transparentplate 62 (i.e., alignment system 50) as shown by a double-headed arrowin FIG. 3, and thereby causes measurement beams L1 and L2 to followgrating mark GM and scans measurement beams L1 and L2 in the Y-axisdirection (the first direction). Accordingly, since grating mark GM andgrating plate 66 are relatively moved in the Y-axis direction,interference fringes are imaged (formed) on readout diffraction gratingsGa and Gb (see FIG. 5a ), by interference between the diffraction beamsderiving from the diffraction beams (±L3 and ±L4) based on measurementbeams L1 and L2.

Beam receiving system 80 is equipped with: a detector 84; an opticalsystem 86 that guides, to detector 84, light corresponding to images(interference fringes) formed on grating plate 66; and the like.

The light corresponding to the images (the interference fringes) formedon readout diffraction gratings Ga and Gb is guided to detector 84 via amirror 86 a that optical system 86 has. In alignment system 50 of thepresent embodiment, optical system 86 has a spectral prism 86 b,corresponding to white light being used as measurement beams L1 and L2.The light from grating plate 66 is spectrally split, for example, intorespective colors of light, i.e., blue light, green light and red light,via spectral prism 86 b. Detector 84 has photodetectors PD1 to PD3 thatare independently provided corresponding to the respective colorsdescribed above. The output of each of photodetectors PD1 to PD3 thatdetector 84 has is supplied to main controller 30 (not illustrated inFIG. 3, see FIG. 6).

From the output of each of photodetectors PD1 to PD3, a signal (aninterference signal) having a waveform as illustrated in FIG. 5b isobtained, as an example. Main controller 30 (see FIG. 6) obtains theposition of each of grating marks GMa and GMb, by calculation, from thephase of the signal described above. That is, in exposure apparatus 10(see FIG. 1) of the present embodiment, alignment system 50 and maincontroller 30 (see FIG. 6 for each of them) configure an alignmentdevice for obtaining positional information of grating mark GM formed onwafer W. Note that the signal as illustrated in FIG. 5b is generated onthe basis of the relative position between grating marks GMa and GMb,and readout diffraction gratings Ga and Gb. Incidentally, the driving ofgrating marks GMa and GMb in the Y-axis direction and the scanning ofmeasurement beams L1 and L2 in the Y-axis direction do not necessarilyhave to be completely in synchronization (their velocities do notstrictly have to be coincident).

In exposure apparatus 10 (see FIG. 1) configured as described above,first of all, reticle R and wafer W are loaded onto reticle stage 14 andwafer stage 22, respectively, and predetermined preparatory works suchas reticle alignment using reticle alignment system 18 and waferalignment (e.g., EGA (Enhanced Global Alignment) or the like) usingalignment system 50 are performed. Incidentally, the preparatory workssuch as the reticle alignment referred to above and baseline measurementare disclosed in detail in, for example, U.S. Pat. No. 5,646,413, U.S.Patent Application Publication No. 2002/0041377 and the like. Further,the EGA following the reticle alignment and the baseline measurement isdisclosed in detail in, for example, U.S. Pat. No. 4,780,617 and thelike.

Here, in the present embodiment, main controller 30 obtains surfaceposition information of wafer W using AF system 40, prior to a positionmeasurement operation of grating mark GM using alignment system 50.Then, main controller 30 controls the position and the attitude in theZ-axis direction (the tilt in the θx direction and the θz direction) ofwafer table 26 on the basis of the surface position informationdescribed above and the offset value that has been obtained beforehandfor each layer, and thereby causes objective optical system 60 ofalignment system 50 to focus on grating mark GM. Note that, in thepresent embodiment, the offset value refers to the measurement value ofAF system 40 that is obtained when the position and the attitude ofwafer table 26 are adjusted so that the signal intensity (the contrastof the interference fringes) of alignment system 50 is maximized. Inthis manner, in the present embodiment, the position and the attitude ofwafer table 26 are controlled in almost real time, by using the surfaceposition information of wafer W obtained immediately before thedetection of grating mark GM by alignment system 50. Incidentally, thesurface position detection of wafer W may be performed by receiving thelight from grating mark GM subject to position measurement, concurrentlywith the position measurement of grating mark GM.

After that, under the control of main controller 30, wafer stage 22 ismoved to an acceleration starting position for exposure with respect tothe first shot area on wafer W, and reticle stage 14 is moved so thatreticle R is positioned at an acceleration starting position. Then,reticle stage 14 and wafer stage 22 are driven in synchronization alongthe Y-axis direction, and thereby exposure with respect to the firstshot area on wafer W is performed. Afterwards, exposure of wafer W iscompleted by performing exposure with respect to all the shot areas onwafer W.

With alignment system 50 equipped in exposure apparatus 10 related tothe present first embodiment described so far, the travelling directionsof the beams diffracted from grating mark GM (GMa and GMb) with aspecific pitch (P1 and P2) are changed using objective transparent plate62 on which diffraction gratings Ga₁ to Gb₂ are formed (utilizing thediffraction phenomenon of the beams), while a typical lens changes thetravelling directions of beams utilizing the refraction phenomenon ofthe beams, and therefore, the increase in size of objective opticalsystem 60 as a whole can be suppressed, compared with the case of usinga lens as an objective optical element.

Further, alignment system 50 related to the present embodiment scansmeasurement beams L1 and L2 with respect to grating mark GM ((GMa andGMb), see FIG. 2a ) in the Y-axis direction while moving wafer W (waferstage 22) in the Y-axis direction as illustrated in FIG. 3, andtherefore, a position measurement operation of the grating mark GM canbe performed concurrently with, for example, a movement operation ofwafer stage 22 toward an exposure starting position that is performedafter wafer W is loaded onto wafer stage 22. In this case, it ispreferable to dispose alignment system 50 beforehand on the movementcourse of wafer stage 22. With this disposition in advance, thealignment measurement time can be shortened and the overall throughputcan be improved.

Further, alignment system 50 related to the present embodiment scans themeasurement beams so as to follow wafer W (grating mark GM) that ismoved in the scanning direction, which allows for the measurement for along period of time. Therefore, since the so-called moving average ofthe output can be taken, the influence of the vibration of the apparatuscan be reduced. Further, if a mark in a line-and-space shape is detectedusing an image sensor (such as a CCD) as a beam receiving system of thealignment system, the other images than the images of lines completelyparallel to the scanning direction cannot be detected (such images aredistorted), when the measurement beams are scanned to follow wafer Wthat is moved in the scanning direction. In contrast, in the presentembodiment, since the position measurement of grating mark GM isperformed by causing the diffraction beams from the grating mark GM tointerfere with each other, the mark detection can be reliably performed.

Further, alignment system 50 related to the present embodiment has, forexample, three photodetectors PD1 to PD3 (for blue light, green lightand red light, respectively) as detector 84, corresponding tomeasurement beams L1 and L2 that are white light. Therefore, forexample, by detecting overlay marks (not illustrated) formed on wafer Wusing the white light, and obtaining the color of the light with whichthe contrast of the interference fringes is the highest beforehand priorto wafer alignment, which output of the three photodetectors PD1 to PD3exemplified above is optimal to be used in the wafer alignment can bedetermined.

Second Embodiment

Next, an exposure apparatus related to a second embodiment will bediscussed. Since the exposure apparatus related to the present secondembodiment is different only in the configuration of a part of analignment system, from exposure apparatus 10 related to the firstembodiment described previously, only the difference will be describedbelow, and with regard to components that have the same configurationsand functions as those in the first embodiment, the same reference signsas those in the first embodiment will be used and the descriptionthereof will be omitted.

FIG. 7a shows a plan view of an objective transparent plate (alsoreferred to as an objective optical element) 162, when viewed from below(the −Z side), that an alignment system (the entire figure is notillustrated) related to the present second embodiment has. Note that thealignment system related to the present second embodiment has anirradiation system and a beam receiving system that are similar to thoseof the first embodiment, though they are not illustrated.

In the first embodiment described previously (see FIG. 3), thediffraction beams (±L3 and ±L4) from grating marks GMa and GMb (see FIG.2a for each of them) based on measurement beam L1 and measurement beamL2 are diffracted toward beam receiving system 80, by diffractiongratings Ga₁ to Gb₂ formed on main section 62 a of objective transparentplate 62 (see FIG. 4b ), while in the present second embodiment, asillustrated in FIG. 7b , the diffraction beams (±L3 and ±L4) fromgrating marks GMa and GMb based on measurement beams L1 and L2 aredeflected in parallel to the Z-axis toward beam receiving system 80, bya plurality of, e.g., four prisms groups Pa₁, Pa₂, Pb₁ and Pb₂ formed onthe lower surface of a main section 162 a of objective transparent plate162, which is the difference between the first embodiment and the secondembodiment. Note that white light is used as measurement beams L1 and L2(see FIG. 3) in the first embodiment, while a plurality of beams withdifferent wavelengths from each other are used as measurement beams L1and L2 in the present second embodiment. Note that the plurality ofbeams with different wavelengths referred to above are illustrated asone beam for the sake of convenience in FIG. 7 b.

Here, since the configurations of the four prism groups Pa₁ to Pb₂ aresubstantially the same except that the disposed positions are different,prism group Pa₁ will be described below. Prism group Pa₁ has a pluralityof, e.g., four prisms P₁ to P₄. Here, the four prisms P₁ to P₄ areright-angle prisms with a triangle-shaped X-Z cross section having thesame length in the Y-axis direction, and are integrally fixed to thelower surface of main section 162 a (or integrally formed with mainsection 162 a). Further, the four prisms P₁ to P₄ are arrayed so thattheir centers are located at a predetermined interval on a diagonal linein β direction. That is, the positions of the four prisms P₁ to P₄ inthe Y-axis direction are different from each other.

As illustrated in FIG. 7b , the positions on main section 162 a and therefraction indices of prisms P₁ to P₄ are each set, so that each of aplurality of diffraction beams from grating mark GMa based onmeasurement beam L1 is deflected in parallel to the Z-axis (i.e., inaccordance with the wavelength of each of the plurality of beamsincluded in measurement beam L1). Prism group Pb₁ is disposed laterallysymmetric with respect to prism group Pa₁ in FIG. 7a , prism group Pa₂is disposed vertically symmetric with respect to prism group Pb₁ in FIG.7a , and prism group Pb₂ is disposed laterally symmetric with respect toprism group Pa₂ in FIG. 7a . Consequently, as illustrated in FIG. 7b ,when measurement beams L1 and L2 are irradiated on grating mark GM via atransmissive area formed in the center portion of main section 162 a,the optical paths of the ±first-order diffraction beams ±L3 and ±L4 fromgrating mark GM based on measurement beams L1 and L2 are bent, by thecorresponding prisms Pa₁ to Pb₂, in almost parallel to the Z-axis towardbeam receiving system 80 (not illustrated in FIG. 7b , see FIG. 3), inthe similar manner to the first embodiment described previously.

Also in the present second embodiment, the effect of suppressing theincrease in size of the objective optical system of the alignment systemcan be obtained, in a similar manner to the first embodiment.

Note that the alignment systems, and the detection systems of thegrating marks including the alignment systems and the detection methodsthereof related to the first embodiment and the second embodimentdescribed above can be changed as needed. For example, in the firstembodiment and the second embodiment described above, as illustrated inFIG. 2a , grating marks GMa and GMb are irradiated with measurementbeams L1 and L2 that correspond to grating marks GMa and GMb,respectively. However, the measurement beams are not limited thereto,and as illustrated in FIG. 2b , a single measurement beam L1 elongated(wide) in the X-axis direction may be irradiated on grating marks GMaand GMb.

Further, in the first embodiment and the second embodiment describedabove, as illustrated in FIG. 2a , grating marks GMa and GMb are arrayedalong the X-axis direction. However, the arrayed direction is notlimited thereto, and as illustrated in FIG. 2c , grating marks GMa andGMb may be arrayed along the Y-axis direction. In this case, theposition in the X-Y plane of grating mark GM can be obtained by scanninga single measurement beam L1 in the order of grating marks GMa and GMb(or the reversed order).

Further, in grating marks GMa and GMb in the first embodiment and thesecond embodiment described above, the grating lines are at a 45 degreeangle with respect to the X-axis and the Y-axis. However, the gratingmarks are not limited thereto, and for example, a grating mark GMy witha period direction in the Y-axis direction and a grating mark GMx with aperiod direction in the X-axis direction as illustrated in FIG. 8a maybe used. In this case, an objective transparent plate (objective opticalelement) 262 equipped with diffraction gratings Gx₁, Gx₂, Gy₁ and Gy₂corresponding to grating mark GMx and grating mark GMy as illustrated inFIG. 8b are used, and thereby an alignment system whose size issuppressed from increasing while the wide detection field of view issecured can be realized in a similar manner to the first embodiment andthe second embodiment described above. Note that in the case ofdetecting grating mark GMx as illustrated in FIG. 8a using the alignmentsystem including objective transparent plate 262 as illustrated in FIG.8b , it is preferable that the measurement beams are scanned in theX-axis direction or the Y-axis direction as needed, for example, using atwo-axes galvano mirror.

Further, objective transparent plate 62 as illustrated in FIG. 4a may beconfigured rotatable around the Z-axis by, for example, 45 degrees. Inthis case, diffraction gratings Ga₁ to Gb₂ that are formed on objectivetransparent plate 62 after such a rotation each have a period directionin the X-axis direction or the Y-axis direction, and therefore,objective transparent plate 62 functions in a similar manner toobjective transparent plate 262 as illustrated in FIG. 8b .Consequently, detection of grating marks GM as illustrated in FIGS. 2ato 2c , respectively, and detection of grating mark GM as illustrated inFIG. 8a can be performed.

Further, objective optical system 60 equipped in the alignment system inthe first embodiment and the second embodiment described above hasdetector-side transparent plate 64 that has substantially the sameconfiguration as objective transparent plate 62 (or objectivetransparent plate 162 in the second embodiment). However, an opticalsystem on the detector side is not limited thereto, but may be a lenssimilar to that of a conventional optical system.

Further, beam receiving system 80 of alignment system 50 in the firstembodiment described above spectrally splits white light with spectralprism 86 b. However, the spectral means is not limited thereto, and likea beam receiving system 380 as illustrated in FIG. 9, white light may bespectrally split toward photodetectors PD1 to PD5 disposed correspondingto the respective colors of light (e.g., blue light, green light, yellowlight, red light and infrared light) by using a plurality of spectralfilters 386.

Further, in the first embodiment described above, white light is used asmeasurement beams L1 and L2. However, the measurement beams are notlimited to white light, and a plurality of beams with wavelengthsdifferent from each other may be used, in a similar manner to the secondembodiment described above. Further, although a plurality of beams withwavelengths different from each other are used as measurement beams L1and L2 in the second embodiment described above, white light may be usedas measurement beams L1 and L2 in a similar manner to the firstembodiment described above.

In the first embodiment and the second embodiment described above,alignment system 50 is used to detect the grating marks for performingthe alignment (the fine alignment) between the reticle pattern and thewafer. However, the marks to be detected with the alignment system arenot limited thereto, and , for example, the alignment system may be usedto detect search marks formed on wafer W (grating marks with thickerlinewidths and rougher pitches than grating marks GMa and GMb),immediately after wafer W is loaded onto wafer stage 22. In this case,as in an objective transparent plate (which is also referred to as anobjective optical element) 362 as illustrated in FIG. 10, it ispreferable that diffraction gratings Ga₃ and Ga₄ with period directionsin the β direction and diffraction gratings Gb₃ and Gb₄ with perioddirections in the α direction, according to the search marks, areadditionally formed avoiding a transmissive area.

Further, the disposed position and the number of alignment system 50 canbe changed as needed, and for example, a plurality of alignment systems50 may be disposed at a predetermined interval in the X-axis direction.In this case, grating marks formed in a plurality of shot areas whosepositions in the X-axis direction are different can be detectedsimultaneously. Further, in this case, a part of the plurality ofalignment systems 50 may be configured movable with fine strokes in theX-axis direction. In this case, a plurality of grating marks formed on awafer can be detected even if the shot map is different.

Further, in the first embodiment described above, the grating pitches ofdiffraction gratings Ga₁ to Gb₂ formed on objective transparent plate 62equipped in alignment system 50 are set the same as the grating pitchesof grating marks GMa and GMb subject to detection. However, the gratingpitches of diffraction gratings Ga₁ to Gb₂ are not limited thereto, butfor example, may be 1/n (n is a natural number) of the grating pitchesof grating marks GMa and GMb.

Further, objective transparent plate 162 in the second embodimentdescribed above has a plurality of prism groups Pa₁ to Pb₂ in order tobend the optical paths of diffractions beams ±L3 and ±L4 from gratingmark GM. However, the optical components for bending the optical pathsare not limited thereto, but may be, for example, mirrors or the like.

Further, the respective configurations described in detail in the firstembodiment and the second embodiment described above, respectively, maybe arbitrarily combined to be implemented.

Further, illumination light IL is not limited to the ArF excimer laserbeam (with a wavelength of 193 nm), but may be ultraviolet light such asa KrF excimer laser beam (with a wavelength of 248 nm), or vacuumultraviolet light such as an F₂ laser beam (with a wavelength of 157nm). For example, as is disclosed in U.S. Pat. No. 7,023,610, a harmonicwave, which is obtained by amplifying a single-wavelength laser beam inthe infrared or visible range emitted by a DFB semiconductor laser or afiber laser as vacuum ultraviolet light, with a fiber amplifier dopedwith, for example, erbium (or both erbium and ytterbium), and byconverting the wavelength into ultraviolet light using a nonlinearoptical crystal, may also be used. Further, the wavelength ofillumination light IL is not limited to the light having a wavelengthequal to or more than 100 nm, and the light having a wavelength lessthan 100 nm may be used, and for example, the embodiments describedabove can also be applied to an EUV (Extreme Ultraviolet) exposureapparatus that uses an EUV light in a soft X-ray range (e.g., awavelength range from 5 to 15 nm). In addition, the embodimentsdescribed above can also be applied to an exposure apparatus that usescharged particle beams such as an electron beam or an ion beam.

Further, the projection optical system in the exposure apparatus of eachof the embodiments described above is not limited to a reduction systembut may be either of an equal magnifying system or a magnifying system,and projection optical system 16 b is not limited to a dioptric systembut may be either of a catoptric system or a catadioptric system, andits projected image may be either of an inverted image or an erectedimage.

Further, in each of the embodiments described above, alight-transmission type mask (reticle), which is a light-transmissivesubstrate on which a predetermined light shielding pattern (or a phasepattern or a light attenuation pattern) is formed, is used. Instead ofthis reticle, however, as is disclosed in, for example, U.S. Pat. No.6,778,257, an electron mask (which is also called a variable shapedmask, an active mask or an image generator, and includes, for example, aDMD (Digital Micro-mirror Device) that is a type of a non-emission typeimage display device (spatial light modulator) or the like) on whichalight-transmitting pattern, a reflection pattern, or an emissionpattern is formed on the basis of electronic data of the pattern that isto be exposed may also be used.

Further, each of the embodiments described above can also be applied toan exposure apparatus that performs an exposure operation in a state inwhich a space between a projection optical system and an object to beexposed (e.g., a wafer) is filled with a liquid (e.g., pure water),which is a so-called liquid immersion exposure apparatus, as isdisclosed in, for example, U.S. Pat. No. 8,004,650.

Further, each of the embodiments described above can also be applied toan exposure apparatus that is equipped with two wafer stages, as isdisclosed in, for example, U.S. Patent Application Publication No.2010/0066992.

Further, each of the embodiments described above can also be applied toan exposure apparatus (lithography system) that forms line-and-spacepatterns on wafer W by forming interference fringes on wafer W, as isdisclosed in, for example, PCT International Publication No. 01/35168.Further, each of the embodiments described above can also be applied toa reduction projection exposure apparatus by a step-and-stitch methodthat synthesizes a shot area and a shot area.

Further, each of the embodiments described above can also be applied toan exposure apparatus that synthesizes two reticle patterns on a wafervia a projection optical system and almost simultaneously performsdouble exposure of one shot area on the wafer by one-time scanningexposure, as is disclosed in, for example, U.S. Pat. No. 6,611,316.

Further, an object on which a pattern is to be formed (an object to beexposed to which an energy beam is irradiated) in each of theembodiments described above is not limited to a wafer, but may be otherobjects such as a glass plate, a ceramic substrate, a film member, or amask blank.

Further, the use of the exposure apparatus is not limited to theexposure apparatus used for manufacturing semiconductor devices, and canbe widely applied also to, for example, an exposure apparatus formanufacturing liquid crystal display devices which transfers a liquidcrystal display device pattern onto a square-shaped glass plate, and toan exposure apparatus for manufacturing organic EL, thin-film magneticheads, imaging devices (such as CCDs), micromachines, DNA chips or thelike. Further, each of the embodiments described above can also beapplied to an exposure apparatus that transfers a circuit pattern onto aglass substrate or a silicon wafer or the like, not only when producingmicrodevices such as semiconductor devices, but also when producing areticle or a mask used in an exposure apparatus such as an opticalexposure apparatus, an EUV exposure apparatus, an X-ray exposureapparatus, or an electron beam exposure apparatus.

Electronic devices such as semiconductor devices are manufacturedthrough the steps such as: a step in which the function/performancedesign of a device is performed; a step in which a reticle based on thedesign step is manufactured; a step in which a wafer is manufacturedusing a silicon material; a lithography step in which a pattern of amask (the reticle) is transferred onto the wafer with the exposureapparatus (a pattern forming apparatus) of the embodiments describedpreviously and the exposure method thereof; a development step in whichthe wafer that has been exposed is developed; an etching step in whichan exposed member of the other section than a section where resistremains is removed by etching; a resist removal step in which the resistthat is no longer necessary when etching is completed is removed; adevice assembly step (including a dicing process, a bonding process, anda packaging process); and an inspection step. In this case, in thelithography step, the exposure method described previously isimplemented using the exposure apparatus of the embodiments describedabove and a device pattern is formed on the wafer, and therefore, thedevices with a high integration degree can be manufactured with highproductivity.

Incidentally, the disclosures of all the publications, the PCTInternational Publications, the U.S. Patent Application Publications andthe U.S. Patents related to exposure apparatuses and the like that arecited in the description so far are each incorporated herein byreference.

While the above-described embodiments of the present invention are thepresently preferred embodiments thereof, those skilled in the art oflithography systems will readily recognize that numerous additions,modifications, and substitutions may be made to the above-describedembodiments without departing from the spirit and scope thereof. It isintended that all such modifications, additions, and substitutions fallwithin the scope of the present invention, which is best defined by theclaims appended below.

What is claimed is:
 1. A measurement device comprising: a mark detectionsystem that has an irradiation system, an objective optical system and abeam receiving system, the irradiation system irradiating a grating markprovided at an object that is moved in a first direction, with ameasurement beam, while scanning the measurement beam in the firstdirection with respect to the grating mark, the objective optical systemincluding an objective optical element capable of facing the object thatis moved in the first direction, and the beam receiving system receivinga diffraction beam from the grating mark of the measurement beam via theobjective optical system; and a calculation system that obtainspositional information of the grating mark based on a detection resultof the mark detection system, wherein the objective optical elementdeflects or diffracts the diffraction beam generated at the grating marktoward the beam receiving system, the objective optical elementattenuating a zero-order beam of the diffraction beam from the gratingmark, and the objective optical element deflecting or diffracting a beamother than the zero-order beam toward the beam receiving system.
 2. Themeasurement device according to claim 1, wherein the objective opticalelement deflects or diffracts the diffraction beam in parallel to anoptical axis of the objective optical system, toward the beam receivingsystem.
 3. The measurement device according to claim 1, wherein theobjective optical element has a first area in which an optical path ofthe measurement beam from the irradiation system is provided, and asecond area in which an optical component to deflect or diffract thediffraction beam is provided.
 4. The measurement device according toclaim 1, wherein the objective optical element includes a plurality ofgrating lines that are disposed at a predetermined pitch in a directionaccording to a period direction of the grating mark.
 5. The measurementdevice according to claim 4, wherein the pitch of the grating line is1/n (n is a natural number) of a grating pitch of the grating mark. 6.The measurement device according to claim 1, wherein the mark detectionsystem further comprises a rotation device that rotates the objectiveoptical element around an optical axis of the objective optical system.7. The measurement device according to claim 1, wherein a position ofthe objective optical element in a direction around the optical axis iscontrolled in accordance with a period direction of a grating of thegrating mark subject to measurement.
 8. The measurement device accordingto claim 1, wherein the grating mark includes a first grating mark and asecond grating mark that have respective period directions in directionsthat are different from the first direction and also different from eachother, the irradiation system irradiates the first grating mark and thesecond grating mark with the measurement beam while scanning themeasurement beam in the first direction with respect to the firstgrating mark and the second grating mark, and the beam receiving systemreceives a diffraction beam from each of the first grating mark and thesecond grating mark, and the calculation system obtains positionalinformation of each of the first grating mark and the second gratingmark based on a detection result of the mark detection system.
 9. Anexposure apparatus comprising: the measurement device according to claim1; a position control device that controls a position of the objectbased on an output of the measurement device; and a pattern formationdevice that forms a predetermined pattern on the object by irradiatingthe object with an energy beam.
 10. A device manufacturing methodcomprising: exposing a substrate using the exposure apparatus accordingto claim 9; and developing the substrate that has been exposed.
 11. Ameasurement method of measuring positional information of a grating markprovided at an object, the method comprising: moving the object in afirst direction, below an objective optical system including anobjective optical element capable of facing the object; irradiating thegrating mark of the object that is moved, with a measurement beam, whilescanning the measurement beam in the first direction with respect to thegrating mark; receiving a diffraction beam from the grating mark of themeasurement beam with a beam receiving system via the objective opticalsystem; and obtaining positional information of the grating mark basedon an output of the beam receiving system, wherein the objective opticalsystem deflects or diffracts the diffraction beam generated at thegrating mark, toward the beam receiving system, the objective opticalelement attenuating a zero-order beam of the diffraction beam from thegrating mark, and the objective optical element deflecting ordiffracting a beam other than the zero-order beam toward the beamreceiving system.
 12. The measurement method according to claim 11,wherein the objective optical element deflects or diffracts thediffraction beam in parallel to an optical axis of the objective opticalsystem, toward the beam receiving system.
 13. The measurement methodaccording to claim 11, wherein the objective optical element deflects ordiffracts the diffraction beam, with an optical component provided in asecond area that is different from a first area in which an optical pathof the measurement beam is provided.
 14. The measurement methodaccording to claim 11, wherein the objective optical element includes aplurality of grating lines that are disposed at a predetermined pitch ina direction according to a period direction of the grating mark.
 15. Themeasurement method according to claim 14, wherein a pitch of theplurality of grating lines is 1/n (n is a natural number) of a gratingpitch of the grating mark.
 16. The measurement method according to claim11, further comprising: rotating the objective optical element around anoptical axis of the objective optical system.
 17. The measurement methodaccording to claim 11, wherein in the rotating, a position of theobjective optical element in a direction around the optical axis iscontrolled in accordance with a period direction of a grating of thegrating mark subject to measurement.
 18. An exposure method comprising:measuring positional information of a grating mark provided at an objectusing the measurement method according to claim 11; and exposing theobject with an energy beam, while controlling a position of the objectbased on the positional information of the grating mark that has beenmeasured.
 19. A device manufacturing method comprising: exposing asubstrate using the exposure method according to claim 18; anddeveloping the substrate that has been exposed.